6.23-6.35 uses of radioactivity Flashcards
In a radioactive substance what decreases over time?
Radioactivity
What is the unit of activity in a radioactive isotope?
Becquerel-Bq
What is the half life of a substance?
The time taken for half of the undecayed nuclei to decay
Can it be predicted when a nucleus will decay?
No
What does half life enable us to do?
The activity of a very large nuclei to be predicted during the decay process
Give three uses of radioactivty
.Household fire(Smoke)alarms .Sterilising equipment .Irradiating food .Tracing and gauging thickness .Diagnosis and treatment of cancer
How is radiation used in smoke alarms?
.Americium is an alpha emitter
.The alpha particles ionise the air and form a current
.If smoke is detected the current drops and a sound is emitted
How is radioactivity used in irradiating food?
.Gamma rays transfer energy to bacteria and kill them
How is radiation used in sterilising equipment?
.Radiation exposed to the equipment kills the microbes
How is radiation used when tracing and gauging thickness of materials?
.Beta radiation is mildly penetrating and can just pass through paper
.A source and receiver are placed either side of the paper
.If there is a drop or rise in electrons this means the paper/thickness has changed
How is radiation used in the diagnosis and treatment of cancer?
.Consuming/injecting a tracer, it passes through the body and an external detector can picture where the tracer has collected in the body which can reveal tumours
What’s the dangers of ionising radiation?
.Tissue damage
.Mutations
What presents a larger long term risk a short or long half life?
A short half life
Give two safety precautions with radiation
.Limiting Patient dose
.Medical personnel leave the room during x rays
What’s the difference between contamination and irradiation?
Contamination lasts for a long period of time-irradiation lasts for a short period of time
Contamination-source must be transferred to an object-irradiation is when a source emits radiation and it reaches an object
What are the two types of treatments for tumours?
Internal and External
Describe the process of an external treatment of a tumour
.A beam of gamma radiation rotates around the body
.It continually focuses on the tumour while only momentarily passing the healthy cells surrounding the tumour
.This ensures minimal damage occurs to the healthy cells
What’s the two problems with treating tumours externally?
.Long time to fully treat the tumour, taking multiple visits around 5 weeks
.Greater risk of long term side effects
How does the internal treatment of tumours work?
.Radioactive material is held within a needle and is injected directly into the tumour
What is the downside of treating a tumour internally?
.A longer period of time needs to be spent in hospital as some radioactive materials are highly radioactive meaning you have to reduce time spent with visitors
What does PET stand for?
Positron emission topography
What happens in a PET scan?
.Radioactive tracer is inserted into the body
.The tracer is tagged to the desired chemical and the tracer travels where the chemical travels
.Scanner reports where the tracer emits radiation
.This produces a 3d visualisation of the body
What are PET scans known for?
.Used to show how effective current treatment is
.Or to diagnose cancer,epilepsy or Alzheimers
Why do isotopes in PET scanners need to be produced near by?
.Tracer has half life of 110 mins so it cannot be stored for a long time before it decays
